/*
 * Copyright (C) 2007-2012 by XDEV Software, All Rights Reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 3.0 as published by the Free Software Foundation.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
 
package xdev.ui;


import java.awt.Component;
import java.awt.event.HierarchyEvent;
import java.awt.event.HierarchyListener;

import javax.swing.SwingUtilities;


/**
 * 
 * Little helper class to focus a specific {@link Component} after a window will
 * be opened.
 * <p>
 * Usage:
 * 
 * <pre>
 * Component componentToFocus = ...;
 * 
 * XdevFocus focus = new XdevFocus();
 * focus.setTarget(componentToFocus);
 * </pre>
 * 
 * or just
 * 
 * <pre>
 * new XdevFocus(componentToFocus);
 * </pre>
 * 
 * @author XDEV Software
 * @since 3.1
 */
public class XdevFocus
{
	private Component	target;
	

	/**
	 * Creates a new focus helper. Don't forget to set the target:
	 * {@link #setTarget(Component)}
	 */
	public XdevFocus()
	{
	}
	

	/**
	 * Creates a new focus helper, and calls {@link #setTarget(Component)} for
	 * <code>target</code>.
	 * 
	 * @param target
	 *            the component to focus
	 */
	public XdevFocus(Component target)
	{
		setTarget(target);
	}
	

	/**
	 * Sets the target component of this focus helper.
	 * 
	 * @param target
	 *            the component to focus
	 */
	public void setTarget(final Component target)
	{
		this.target = target;
		
		if(target != null)
		{
			target.addHierarchyListener(new HierarchyListener()
			{
				@Override
				public void hierarchyChanged(HierarchyEvent e)
				{
					if(e.getID() == HierarchyEvent.HIERARCHY_CHANGED && target.isShowing())
					{
						target.removeHierarchyListener(this);
						SwingUtilities.invokeLater(new Runnable()
						{
							@Override
							public void run()
							{
								target.requestFocus();
							}
						});
					}
				}
			});
		}
	}
	

	/**
	 * Returns the target component which will be focused.
	 * 
	 * @return the target component
	 */
	public Component getTarget()
	{
		return target;
	}
}
